Fuel system unit



Jan. 8, 1935. f IF. w. HECKERT 1,986,971

FUEL SYSTEM UNIT A TTORNEY a pump feedfuel system for `aircraft.

, pump,l bellows-type relie i `without fuel traps.

suitable adapters todrive the' power driven rotary afuel control cock that is'rea i ing the power driven fuel pump and relief valve by-passV to the j Patented `Jan.*8, j1935 k i MTF-D,y YSTAT115 'rm-:NT OFF'ICE j This invention relates to new and useful imi provements in fuel system units especially adapted for aircraft.` Y l" f It is one of the principal objects of my invenvtion `to provide a simple,` compact, light weight and efcient fuel system'unit combining into one it the'fseveralvelements required in `duct for supercharged engines. Figure 6 is an end viewfofv the fuel cock, showing the position `of "the variousinlet ports and flange drilling to per-1l mit indexing the latter. And Figure "l isla sectional view taken through `the `piston and valves 5 on `the line 'l-'l of Figure 1 i l `Referring to the drawingsfor a detailed de- 'scription of my invention, the numeral 1 desig- `nates a main housing, `preferablymade of cast aluminum alloy,` and provided fwith mounting Hbosses 2, 3 and 4 spaced on the outer surface of the housing.` i i Vw i In the `center of the housing 1 there lis a large axial vbore.5 fitted witha liner 6, preferably of bronze, for a hand-operated wobble pump impeller 7, 'Ihis impeller is secured upon a shaft 8, concentric with the bore 5 andliner 6, andhas one end journalled in a boss 9 `formed integral,` pump by a flexible shaft, hydraulic motor cr elecwith thehousing 1 andon one side thereof, `tric motor, Vor other suitable "available ipower" Y"IheJopposite endf of the` shaft f8 projects *means through acover plate 10 in which itis journalled, It is another and hastted to a boss 11 integral with the latter,

'Ihe `extreme vouter end i fa packing gland nut 12'.

of thisshaft, where it projects beyond the nut 12, is serratedand fitted with a lever arm 13 by which the impeller '7 may be oscillated through a` linkage '(not shown) from the pilots cock pit.

' The impeller l has two oppositely disposed arms `1li and 15, whose outer ends, where they Contact l] the liner, are formed with downwardly extending arcuate flanges 16 andi` 17 respectively. `(See Figure 2).- As "-fshown in Figures 2: and 7,

this impeller is provided with two oppositelyv disposed parts 18 and 18a extending vthrough `it. These` parts are positioned adjacent each otheraxially and'comprise cored passages extending;- through 1 the hub` portion 'la of the impeller 'l `:and surrounding the :shaft H8. Each of the ports' 18 andglthus formed communicateswith a divided discharge cham- ,ber*19 abovethe impeller and a divided suction chamber 20 below the latter. (See Figures `2 and 7:)"3 l i x Secured in the suction chamber 20 below the impeller ,'7` is an inlet valve box 21, comprising an inverted yoke22 positioned over an inlet port 23 in the liner 6 belowthe shaft 8. In the oppositely inclinedsidesof the `yoke 22 are ports 24fand 25.`

communicatingwith the chamber 20 above the valve box and the inlet port 23 below'it.

The ports 2,4 and 25vare adapted to beclosed by ycheck valves 26 and 27 pivoted to pins 28, 28

mounted on the cover 10. At its vertex `thevalve lbox is provided with anaxial groove in which there is positioned a packingrstrip 29' to render centralized un It is another object of"my"inventionto provide a fuel `control cock, strainer, hand'istartingV and lemergency wobble pump, Vpower driven rotary f valve and `puppet type by-pass valve so arrangedJ as to obtain the shortest and most( direct ow of fuel from the cock` inlet ports to the powerdrivenfpunip discharge l Itis another object of my inventionto provide object of roy invention toprovide dily attached 'to the main housing in a manner" that will allow it to be set in ainumber of positions at an angle vof 45v degrees from the vertical tofacilitate connect-` ing the fuel lines from the fuel tanks and extending a remote cock control to `the pilotscock-pit.

Itis` another object of my invention tofprovide means t`o permitthe removal of the fuel'cock from the unit and substitute other type cocks, or to op-f erate the unit satisfactorily without'a. 'fuel cock directly attached toit; Another objectof my invention is to provide a unit" of i several elements, assembled in"v such a manner that replacement of parts'can be readily effected, thus facilitating eld'repairsandeliminating the necessity for rejection of the entire unit. r" f l Other important and incidental objectsvwill'be brought out in the following specification and particularly set forthin the claims annexed thereto.` In `the accompanying drawingsillustrating my invention, Figure l is a plan view of the unit with thefueljcock removed.Vv Figure `2 is a cross-sectional"view taken through `the unit on Vthe "line 2;-2 of Figure 1, showing the fuel cock attached to the unit. Figure 3`- is a rear view of theunit,"

' partially broken away to showthe power driven r lfuel pump and itsl drive mechanism in section.

Figure 4 isa partial side view of the'unit, shcwl hand pumpinletl` Figure 5 a bottom view'of the lbellows relief valve cover, showing the connection for the carburetor air l with radial ports'52, and, in the top of the cover,.

liquid tight the contact between the valve box and the outer concentric face of the impeller arm 14.

(See Figure 2.) s

The port 24 communicates with that portion of the suction chamber 20 which serves the port 18 through the impeller 7, and the port 25 communicates with that portion of the suction chamber 20 which serves the port 18a through the-impeller 7. (See Figures 2 and 7.)

Above the impeller in the discharge chamberV 19, isa discharge valve assembly 30 having a valve body 31 whose lower center portion is fitted with a packing strip 32 to form uid-tight seal between the valve assembly and the top concentric face of the impeller arm15. (See Figure 2.)

Provided in one of the lower inclined faces of the valve body 31 and above the port 18 is a passage 33 whichcommunicates with a discharge port 34 formed in the top of the valve body and that portion of the discharge chamber 19` separated from the port,18El 32. (See Figure 2.)

Formed in the opposite lower inclined face of the valve body 31 and above the port 18a there by the packing strip is another ypassage 33a adjacent the passage 33 and vcommunicating with another discharge port 34 adjacent the port 34 and likewise formed in the top of the valve body. This passage 33a communicates with that portion of the discharge chamber 19 into which the port 18a discharges. (See Figure 7.)Y x Y Each of the ports 34 and 34a is fitted with an independent check valvey 35 and 35HL pivoted on pins 36, 36 likewise secured tothe cover 10. Now, when the, impeller 7 is through the ports 18 and 18a into the divided chamber 19, and thence alternately discharged through the yports 34 and `.348,.a port 371 in the cage 6 and a passage 38 to a check valve unit 39.

(See Figures 2 and 7.) This check valve unit 39 isfremovable as a whole, comprising a cage 40 preferably made of bronze, and received by a bore 41. concentric with the passage 38 and in the top of the housing 1. At its upper end the cage is provided with a flange 42 andin its sidewall, below the flange,

witha lateral port 43 that communicates with a,A

lateral passage 44 to a discharge flange 45 in the cover 46 that has a dependingboss 47 boredto provide a guide for the stem 48 of a checkfvalve 49; This valve eiectively closes a port 50 inthe lbottom of the cage 40 in alinement with the pasi sage 38. f

lSurrounding the stem 48, `and a reduced portion of the boss 47, is a helical compression spring 51, to effectively hold this valve closed when the hand pump is not in operation.

The boss 47 above the stemv 48, is provided with a threaded hole 53 communicatingwith the latter and to which the gasoline pressure gage line may be attached.

The valve cage and cover are secured to the.

an effective liqplug (not shown) oscillated, liquid will beA vdrawn alternately through the ports 24 and 25 j linto the-divided chamber 20 At its rear end the recess 57 and the end of the cylindrical screen are closed by a lflanged cover 62 provided with a gasket 63 and held in place by a swing clamp bar 64 in contact with its outer face. (See Figure 2.) This strainer unit, if clogged or defective, may also be easily removed without disturbing the other units.

Below the strainer unit the housing l is formed with a downwardly sloping cavity 65 in whose lower end is a threaded boss 66 to receive a drain Above the strainer, an inlet passage 67 to the` strainer unit terminates in a threaded hole 68 in the bottom of a counter-bore 68*i formed in the rear inclined face 69 of the housing 1. vThis inclined face 69 is circular, as

. shown at Figure 6, and is provided about its periphery with equally spaced holes 70, in this case twelve, to receive a three-way fuel cock unit 71. The latter hasaflange 72 and three corresponding holes 73 that register with the holes 70 to V.to effectthe most direct connections with the various fuel tanks, the unit may be adjusted tc the desired angle through the holes and 73.

s The valve unitis conventional in form, particularly for aeronautical work, and comprises a conicalbody 76 flanged at its outer end and provided with a cover 7,7 in which there is journalled. a valve stem 78. Within the body 76 the stem is enlarged, being provided with a tapering, lami nated valve 79, preferably of cork and .secured upon the enlarged portion of the stem 78.

'Ihe valve 79 has an axial passage 80 communicating with a radial port 8l and discharging through a port 82 in alinement with the hole 68. Now, when the valve is rotated to bring the radial port 81 into registry with one ofthe ports 75, passage for the fuel will be provided through the fuel cock to the strainer.

As shownin Figure 2, the valve is in the closed position and adapted to be rotated bya yoke 83 securedto the end of the valve stem where it projects through the cover 75. 'Ihis yoke is engaged by a similar fltting (not shown) on the fuel control shaft that projects downwardly from the. instrument panel.

Connected with the inlet passage 55, below the port 23, is a by-pass 84 passing upwardly around the hand pump to a power driven vane type fuel pump unit 85 positioned in the upper forward portion of the housing' and below the passage 44, to which it discharges. This pump unit is removable as a whole and is fitted in a bore 86 in the housing 1, parallel with the bore 5.

- The pump unit comprises front and rear bronze bearings 87 and 88 fitted in the bore 86 and between which there is secured a steel liner 89. Rotatable within the liner 89 is a shaft 90 that is journaled in both bearingsv and extends rearwardly through a conventional shaft packing 91 in a bearing lock nut 92 and retained by a gland nut 93 received by a threaded recess in the nut 92.

Where the shaft extends into the steel liner 89, it is rotatable within an eccentric bore 89a in the latter, and has a transverse slot 94 in Cil en A shaft 90 and surrounding `the `nut fully across the bore 89 and actuated byit.

Where the ends ot-v the 'vane 95 `contact the `wal1s of theeccentricbore, theyarefitt'ed with steel rockers 96, 96 tol provide a yieldable self Y aligning contact with the liner walls.

Fuel isad 'tted tothe inl t side of the pump through vanjinlet port 97 communicating withV the upper end of `the by-pass 8'4 and withthe'1 `bore'89. -Dischargeoffuel from the pump 85' is effected through anotherwan'd opposite' port 98 in the liner89 andconnected with thepassage 44.-` (See FiguresZand 3). i Y

The rear Vface of the"housing `1 is provided with a circular ilangeV 99 `concentric with the 92.'- `Fitted` to this flange isa rectangular fadapter plate 100,

secured to the housing by screws 101. Bolted tof thisadapter platelisa companionplate 102.` Con- 105 by which a right angleldrive adapter 106 [may be attached at a convenient `angleto receive a flexible drive shaft 107. 'This drive adaptfer` 106, as shown at Figure 3, comprisesan oblong housing 108 having a circular flange 109 that receives the screws 105. anda `:tennon 110 i below the flange `that is received by the bore 103 r "to aline the adapteriwith' the shaft 90.

Journaled inball bearings 111` and'l12 on the ends Yof the housing, is a hollow shaft 113 havingv integral therewith a bevel gear 114. One

"end of theshaft 113, adjacent the plate 102 is vprovided with `a square breached -hole 115 to re`` ceive therein thesquare 'end 116 ofthe vshaft 90 where it extends "into the former. 'i (See Figures ona shaft 1l`8",fat right angles extension of the housing 108@ This "shaftyis rodated byv the flexible shaft 107 fromithe engine,

or maybe directly connected to an electric motor or other source of power. (SeefFiguresf 3 and 4).` l

When

it will rotate the pump 85, whereupon fuel will be drawn in through the fuel cock 7l, strainer 56 and by-pass 84, for discharge by the pump through the port 44 to the outlet flange 45. When starting the engine, the hand-operated pump may be utilized either to supply the initial fuel to the engine carburetor or to prime the motor-driven pump. Y

When excessive pressure is built up in the outlet passage, either through reduced` consurnption of fuel or an excess supply thereof delivered by either of the pumps, relief is afforded through a relief valve 119 connectedby a cored passage 120 with the passage 44 and port 98.

This relief valve is of the bellowsytype contained within abore 121 in the front of the housing 1. Through a counterbore 122 the bore `121 communicates with the passage 120. This counterbore receives a flanged valve f seat V123'provided with a tapering aperture 124. This-valve seat is adapted to be closed by `a disovalve 125 secured to the upper end of a valve stem 126 whose lower end is slidablygreceived in a bore 127 in the upper end of a flanged adjusting stud128. i x y .H

Surrounding the valve stemand between the valve'against its seat.

`like cylinder 130 as shown at centric with "a `bore f 103 in the centerof the plate `102 isa bolt circle havinga seriesjof equally "spaced holes 104 tol receive throughthem screws gear A114 isl anotherbevel journaledgin a right angle vthe drive adapter shaft" 113 is rotated.`

parts conveniently and accessibly` valve 125 and theflange 128e, onthestud 128, is a helical cornpressiorrspring 129`to` force the Secured to the underside of the valve 125, withinthe bore 121, is an expansible metallic bellows- Figure 2.

The upper end `of this cylinder is-closed by the valve 125, while its lowerV endis soldered and effectively seals thespace betweenthe cylin- Vto a circular flange 131 thatcovers the bore 121 threaded aperture inwhich theadjusting stud i 128 is received; On the lower'outer `face of the *cap I have provided a boss 133 surrounding the aperture and threaded internally to` receive a check nut 134/ffor the adjusting stud and externally for a cover 135 tn completely sealthe ad-` justing stud and check nut against leakage. `This cap and the Vflange 131 are secured to the housing liby screws 132n passing through therformer and received by threaded holes in thehousing.`

l Inoneside "of thebore 121, and immediately y below the valve 125, there is provided an outlet slot 13.6 that communicateswith a fuel relief passage.137 cored in the housing 1 `andformed downwardly behind the" relief valve,r terminating at the junction of the by-'pass 84 with the passage 55 orithe inletside of both the hand and motoroperated pumps.

When an excess of fuel isforced through `the `valve `125, it is returned to `theinlet side'of` the pumps by this passage 137. The cylinder 130,

4being collapsible; forms a'. tight seal across the' `open end of the bore 121, and when the excessof pressure is relieved, the valve will be returned` to its Seatbythe spring 129. l u i In order to stabilizethe operation of my `presi 'sure relief valve so that it `may be utilized on either "upercharged orl non-supercharged engines with equal efhcienc'y,'1 have providedan airline connection 138 to a boss.139 formed on municates with the space within the cylinder 130,

and is providedY with'air pressure through a tube "connected with theengine carburetors on `supercharged engines.

`(See Figures 2 and 5). When used with non-supercharged engines, this air line is disconnected and air at atmospheric pressure `is admitted to the cylinder.

Existing conditions may require that the pump y shaft 90 be rotated in a direction opposite to that indicated Aby the arrow at `Figure 2. When such a condition exists, the pump shaft 90, bearings 87 and 88 andthe liner 89 are withdrawn from the bore 86 and indexed 1809. When re-inserted in the bore, dowel pins 87EL in the front bearing enter the lower dowel pin holes in the housing 1, asshown at Figure 3.

With the liner, and the bearings to which the former is pinned, thus indexed, the position of the inlet and outlet ports 97` and 98 is. reversed. Whenthe direction of rotation of 'the shaft is reversed, fuel will be drawn in through the port 98 fromthe ny-pass 84 and discharged through the port 97 into the passage 44.

1t will thus be seen that I have provided a compact and extremely eiicient pumping unit, with low suction arranged for inspection, `adiustment or repair. The possibilthe side of the cap 132. Thisconnection com-' lift without traps, and with all ity of vapor lock is also eliminated in my pumping unit. f

Having described my invention, I claim:

1. A fuel system unit comprising ahousing, a hand-starting and emergency pump in the central portion thereof, a power-driven pump in said housingv at one side of the` hand pump,

means in said housing for admitting fuel to the` handpump, and a fuel by-pass formed in the housing around the hand pump to the powerdriven pump. 1

2. A fuel system unit comprising a housing, al' hand-operated pump in the central portion f thereof, a. power-driven pump-,also in said housing at one side of the hand pump, means in said `housing for admitting fuel tothe handpump, a

fuel by-passV formed in said housing around the hand pump to the power-driven pump, and a common discharge in said housing for both pumps. I

3. A fuelsystem unit comprising a housing, a

.hand-operated pump inthe central portion thereof, a power-driven, pump also in said housing-at one side of the hand pump, means in said vhousing for admitting fuel to the hand pump, a fuel by-pass formed in said housing around the hand pump to the power-driven pump, a common discharge means in said housingfor both pumps, and a relief valve in said housing `in communication with said vdischarge means. -K

4; A fuel system unit comprising a housing, a hand-operated pump in the centra/l portion thereof, a power-driven pump also in said housing at one side ofthe hand-pump, means .the junction ofA saidA by-pass' and the vfuel inlet to the hand pump. l

5. 'A fuel system unit comprising a housing, a hand-operated 'pumpy in the central lportion thereof, a power-driven pump also in said housing'at one side yof the hand. pump, a fuel inlet control cock on said housing, a screen in said housing with which the fuelinlet control cock is in communication, a passage in said housing between the screen and the hand pump, and a bypass from said passage around the hand pump to the motor-driven pump.

Y 6. A fuel system unit comprising a housing, a

Ahand-operated wobble pump in the central portion thereof, means for delivering fuel to said wobble pump, a power-driven pump in said housing at one side of said wobble pump, and a passage in said housing extending around the wobble pump from its inlet end to the power driven pump to deliver fuel to the latter.

e 8. A fuel system unit comprising a casting, a hand-operated pump in the central portion of said casting, a power-driven pump in one upper side portion of the casting and a fuel inlet in the other upper sideof the casting, a screen insaid casting below the fuel inlet and in communication therewith, a passage in said casting extending from said screen to the hand pump, a bypass in the casting from said passage to the power-driven-pump, a common discharge passage in the upper portion of the casting for both pumps, and a relief valve in said casting communicating with said discharge passage, below the power-driven pump and at the left of said by-pass.

9. A'fuel system unit comprising a housing, a hand pump in said` housing, a power-driven pump also in saidhousing, independent fuel passages in said housing. ,leading to the hand pump and the power-driven pump whereby said pumps may operate in parallel, and a common discharge for both pumps. a

10. A fuel system unit comprising a housing, a

hand-starting and emergency pump in said housing, a power-,driven pump also in said housing, independent fuel passages in said housing, leading' to the hand-starting pump and the power-drivenpump whereby said pumps may operate in parallel, anda common discharge for both pumps, in the top forward part of the housing to permit any trapped air and vapors to readily and quickly pass out of the fuel channels.

FREDERICK W. HECKERT. 

